Go to Central administration > Manage service applications > Search service application > Crawl rules .
Use the belwo configuration and create a crawl rule.
Path = ://*/AllItems.aspx
Crawl configuration = Exclude all items in this path (check “Exclude complex URLs (URLs that contain question marks – ?)”)
Specify authentication = Use the default content access account (or use other suitable option for your project)
Now do a full crawl, then all the */allitems.aspx pages will be excluded from crawling.
Edit: This method also excludes the documents in that library , if there is no other link to those documents in other pages.
Also, if you want that only for one Search results page the allitems.aspx needs to be excluded , then you can just edit the Search results webpart and edit the Query to add this --> -filename:allitems.aspx
Here you don't need any central administration access or full crawl to be done.
Please see this blog.